According to people familiar with the investigation, US Special Counsel Robert Mueller is investigating former White House national security adviser Mike Flynn’s alleged role in a plan to forcibly remove Turkish Muslim cleric Fethullah Gülen living in the US and deliver him to Turkey in return for millions of dollars, according to The Wall Street Journal (WSJ).

Under the alleged proposal, Flynn and his son, Mike Flynn Jr., were to be paid as much as $15 million for delivering Gülen to the Turkish government.

The FBI questioned at least four people in regards to a December 2016 meeting in New York at the “21” Club. Discussions between Flynn and Turkish representatives supposedly took place there, and they allegedly included how to transport Gülen on a private jet to the Turkish prison island of İmralı.

Ankara accuses Fethullah Gülen and his Gülen Movement of orchestrating the failed military coup in Turkey, in July 2016.